A third runway will “never” be built at Heathrow as politicians will always put their election campaigns over national interests, the head of British Airways’ parent company has claimed.

Nimbyism will stop politicians from doing anything with the findings of Sir Howard Davies’s Airports Commission, Willie Walsh, the chief executive of International Airlines Group (IAG), said.

“There will never be a third runway at Heathrow. I just don’t see it happening as it’s politically too difficult,” Mr Walsh said at a conference in London.

“This is politics with a small ‘p’. The national interest gets lost as the individual politicians look to understand how this will impact on them getting elected.”

The commission’s final report, which will recommend where to build new runway capacity in the south-east, will “get handed to politicians who will do absolutely nothing with it”, Mr Walsh told an audience, which included Sir Howard, at the Airport Operators Association conference.

The aviation veteran delivered his damning verdict on how the latest tortuous debate on runway capacity in Britain will play out, after Sir Howard defended the decision to deliver his final report in 2015, after the next General Election.

“If you produce a report in the run-up to the election then the chances of it becoming a political football are quite high,” said the former chairman of the Financial Services Authority.

“Realistically this is the sort of decision that gets made early in a Parliament if it gets made at all,” said Sir Howard.

However the airports commissioner conceded that any new runway would take “a decade or more to come into effect” and the process will likely be delayed by legal challenges. The commission already faces the threat of a judicial review after campaign group, Stop Stansted Expansion, initiated legal proceedings earlier this month.

The Airports Commission is currently assessing 58 submissions to its consultation on runway capacity before producing a short-list in December. Commissioners will look at whether a “package of proposals”, for example a runway at more than one airport, could be put together, Sir Howard said.

Separately, Mr Walsh said IAG would look “very carefully” at bringing a legal challenge at the European level over the Italian Government’s financial lifeline to struggling flag carrier Alitalia.

“I believe it is blatant state aid,” said Mr Walsh. “Europe has got to stand up and implement the rules that exist. State aid is damaging to this industry. It has led to a fragmented and unprofitable industry in Europe where unprofitable airlines with no prospect of becoming profitable continue to drag down airlines that are trying to do the right thing and compete in a commercial manner and the Commission needs to stand up.”

Mr Walsh attacked the European Commission for spending a “fortune” on preventing Ryanair from taking over Aer Lingus “and yet they turn a blind eye to what is happening in Italy”.